The human cardiovascular system is composed of the heart and blood vessels through which blood moves nutrients to cells, tissues and organs, and carries metabolic products away for use or disposal. Since the capillaries are porous, there is a continual exchange of nutritive and waste materials between the blood stream and the body tissues. There is also a continual net flow of plasma fluid out through the capillary walls, adding to the tissue fluid. The blood vessels in the microcirculation region can reabsorb some of the lost fluid, but excess fluid and some plasma protein is returned to the venous circulation path via an elaborate system of collecting vessels, called the lymphatic system. Proper functioning of the lymphatic and muscle pump systems ensures that excessive lymph will not accumulate in the lower extremities. This is important since accumulation of lymph leads to edema with side effects of pain, fibrotic tissue changes, dermal ulceration, infection and, possibly, loss of limb. When trauma or paralysis prevents a patient from exercising the legs, the natural pumping action of the calf muscles is lost, and the result can be lymphedema and tissue fibrosis. Thus, people who are most likely to have lymphedema are sedentary adults such as those recovering from surgeries and those with spinal cord injuries. Lymphedema can also lead to more serious effects such as venous stasis with secondary deep venous thrombosis (DVT). In turn, DVT may lead to life threatening pulmonary embolism. Since DVT has the greatest possibility of occurring in a patient within 90 days of a spinal cord injury, it is advantageous for treatment of edema begin during this period. Generally, it is highly advantageous to treat edema as it is occurring or as soon as possible thereafter.
Where the treatment for edema is not commenced upon occurrence, treatment to reduce the swelling can be lengthy and uncomfortable for patients.
All prior art compression devices known to the inventors operate pneumatically, are bulky, are not portable, and are not responsive to edema levels. That is, none of the devices function to monitor the edema or sense the occurrence of edema for initiating the compression.